There are three basic generic types of single cup coffee and tea brewers: the cone drippers that have a drip mode, the infusers that have an infusion (i.e. steep) mode, and the Espresso plungers that force brewed coffee through a filter.
FIG. 1A illustrates a cone dripper 102 using a Number 2 conical coffee filter 103. To use the cone dripper 102, the cone dripper 102 is placed on top of a coffee cup 105, the conical coffee filter 103 is inserted in the conical container 104, coffee grounds and hot water are then added to the conical coffee filter 103. The coffee brews in the filter paper and the brewed coffee slowly drips through the drainage holes 106 located on the cone dripper base 107. The time it takes for the brewed coffee to complete the dripping is herein called the drip time. The cone dripper typically has three drainage holes, and the rate of dripping, herein called the drip rate, depends largely on the diameter of the drainage holes. The advantage of the dripper is that it is cheap to produce and easy to use. However, there are several deficiencies of the generic cone dripper:                1) The user has no control of the drip rate;        2) there is no zero infusion mode, i.e. the time the water and coffee grounds steep before dripping starts; and        3) The size of the cone dripper is limited by the capacity of the conical filter used.        
FIG. 1B illustrates the most common infuser type coffee brewer: The French press 109. It has a French press container 110, typically a glass or plastic beaker. It also has a French press plunger 108 constructed out of a handle 113 attached to the metallic filter 114 and slidingly attached to the French press lid 111.
The French press 109 makes brewed coffee as follows. The French press plunger component 108 is removed from the French press container 110, coffee grounds and hot water are then placed in the French press container 110, and the French press plunger component 108 is then inserted in the French press container 110 with the French press lid 111 removably attached on the top of French press container 110 with the metallic filter in an upward position as illustrated in FIG. 1B. The coffee grounds and hot water are allowed to steep for several minutes. Then the handle 113 is pushed down thereby compressing the coffee grounds to the bottom of the container while the brewed coffee without the grounds remain above the metallic filter 114. The brewed coffee is then poured into a cup for drinking.
There are several deficiencies of the generic French press:                1) some coffee grounds typically get in the brewed coffee after pressing is completed;        2) the grounds remaining in the French press container have to be disposed of; and        3) the press time (similar to the drip time of the dripper) gives the user very little control of the process.        
FIG. 1C illustrates a generic version of the Espresso plunger assembly 115. It is constructed out of a plunger component 116 that has a plunger base 117 that snugly fits in the Espresso plunger container 118. Espresso plunger container 118 is open at the bottom. Attached to the bottom is an Espresso plunger filter 119. The Espresso plunger assembly 115 fits on a coffee cup 105 as illustrated in FIG. 1C
To use the Espresso plunger assembly 115, the Espresso plunger container 118 with the plunger component 116 removed is seated on top of the coffee cup 105. Coffee grounds and hot water are added to the Espresso plunger container 118 and brewing starts. The plunger component 116 is then inserted in the top of the Espresso plunger container 118 and pushed down, the plunger base 117 forcing the brewing liquid through the Espresso plunger filter 119 into the coffee cup 105. The Espresso plunger filter 119 lets the brewed coffee pass through and fall into the cup, but is fine enough to prevent the coffee grounds to pass through. When the pressing is done, the coffee is ready to drink.
FIG. 1D illustrates an opened cone filter. FIG. 1E shows the flattened cone filter as sold commercially (typically a number of them are stacked, one on top of the other). FIG. 1F illustrates a basket filter in the shape it is sold commercially (typically a number of them are stacked, one inside the other). FIG. 1G shows the basket filter opened flat as a filter paper disk. FIG. 1H show cross sections of a cone and cylinder with dimensions as shown. Since the volume of a cone is ⅓ the area of the base multiplied by its height, and the volume of a cylinder is the area of the base multiplied by its height, FIG. 1H illustrates that the profile of a cylinder is much smaller than a cone with the same volume. Both cross sections have a volume of approximately 33 cubic inches.                a) There are several proprietary single cup coffee brewers. Five of the most popular are:                    Clever™ Coffee Brewer (uses a Number 2 conical coffee filter) and its larger version, the NEW Clever Coffee Brewer (uses a Number 4 conical coffee filter). These are covered by U.S. Pat. No. 6,327,965.                        b) Incred 'a Brew™ Coffee Maker: Also covered by U.S. Pat. No. 6,327,965. Uses a metal filter.        c) AeroPress™ Coffee Brewer (uses a proprietary filter paper). Covered by U.S. Pat. No. 7,849,784.        d) Bonavita BV4000ID Porcelain Immersion Coffee Dripper. (Uses a Number 4 conical coffee filter). Flow is turned on or off using a lever.        e) Frieling Coffee for One™: Has drip mode only, uses a metal filter        
The first four proprietary coffee brewers listed above all have an infusion mode, however only the AeroPress uses filter paper with a brewing container that has a flat bottom, and is the most popular commercial product implementing the Espresso plunger function. Furthermore, although the first four proprietary coffee brewers have an infusion mode and a drip mode, none can control the drip rate. The AeroPress proprietary coffee or tea brewer uses proprietary filter paper, comes with many parts, and many find it difficult to use.